1. Field of the Invention
The present invention relates to a positioning technique, and more particularly, to a positioning technique for localizing a moving device.
2. Description of Related Art
Due to rapid progress in technology, the industry develops towards automatization, such that repeated, trivial, and toilful labour intensive work is carried out by automatic machines. With regard to automatic machines, service event is determined by a positioning accuracy. The conventional positioning technique is described below.
For example, a conventional automatic carrier can take goods from a place to another place. The automatic carrier moves by wheels. Further, the automatic carrier is positioned by an odometer and a direction sensor. It should be noted, if the automatic carrier passes through a bumpy road, the odometer and the direction sensor may make errors easily. Over a long period of time, the errors may be accumulated larger and larger, so that the automatic carrier may fail to take goods from a place to another place.
For this reason, in the conventional technology, an environment video camera is provided to help to localize the automatic carrier. First, a calibration of the environment video camera should be carry out to establish corresponding relation between an image reference coordinate and a world reference coordinate. A picture of the automatic carrier can be transformed from the image reference coordinate to the world reference coordinate according to calibration parameters of the video camera so as to achieve the localization of the automatic carrier. It should be noted, calibrations of the environment video camera should be carry out again, when a focus or a visual angle of the environment video camera is changed, so that a efficiency and a elasticity of real operation would be direct influenced. Beside, only using the environment video camera to localize the automatic carrier would be fail or incorrect when the automatic carrier is hidden by an environment object and results in that the automatic carrier can not be viewed by the environment video camera.